Three years ago long standing best friends 37 years, (he was our best man, she was our eldest daughters godmother), moved to the other side of the country to live nearer to their daughter. We used to see them a few times a year as they only lived 40 mins away. I was in a demanding job at the time, so the new distance would have meant no day visits and overnights were not really on as I used to use weekends to catch up with everything. Anyway after a few months I had heard nothing, no new address, no contact so I sent emails (not on FB), and made phone calls, still nothing. I continued to periodically e mail and telephone, but still no contact. I then sent a request to her daughter on FB (clear it was not a really active account) and followed it up with a call. She then rang back but 3 years after the move. She had been really unhappy in the new location, they had moved from a middle class town (upmarket actually) to a very much less affluent part of the country, and she said she couldn't talk about it without crying.
I had then retired so we visited on our way back from our DS in London, and our friends have now moved within the same town, so we then went for a weekend! Friendship fully restored. Her DiL, has only just started taking to her, as they use to live near each other , and was silently furious (I believe), that once they moved across the country, she lost the free holiday childcare!!
So do not give up, I told her I really like their new move location, she said that compliment has helped her to settle in more, she does still regret moving from the West to the East, but loves being near to and seeing her DD on DD way home from work when she drops in for a coffee.
Also
My DS, had a very close friend all through school and up until DS went to Canada, at 27. His friend went with him, but never 'managed', to find any work, so for a year DS picked up all the bills! DS came back to the UK at 36 (failed long term relationship. - I so wanted to hug the girl, who was lovely but not in our opinion the right girl, and say thank you, he wouldn't have come back otherwise!!!). After being home for 18 months DS invited his friend to his sisters engagement, but the friendship never repaired. So some friendships can get over 'stuff' and some can't.
What I hope this illustrates is that very few people have not been through a long term friendship breakdown. You belong to a big family club, It is NOTHING you have done!